Improving the perfomance of elevator systems using exact reoptimization algorithms

Improving the performance of elevator systems using exact reoptimization algorithms

An Exact Reoptimization Algorithm for the Scheduling of Elevator Groups

The task of an elevator control is to schedule the elevators of a group such that small waiting and travel times for the passengers are obtained. We present an exact reoptimization algorithm for this problem. A reoptimization algorithm computes a new schedule for the elevator group each time a new passenger arrives. Our algorithm uses column generation techniques and is, to the best of our know...

Reoptimization in Branch-and-Bound Algorithms with an Application to Elevator Control

We consider reoptimization (i.e., the solution of a problem based on information available from solving a similar problem) for branch-and-bound algorithms and propose a generic framework to construct a reoptimizing branch-and-bound algorithm. We apply this to an elevator scheduling algorithm solving similar subproblems to generate columns using branchand-bound. Our results indicate that reoptim...

Online-optimization of multi-elevator transport systems with reoptimization algorithms based on set-partitioning models

We develop and experimentally compare policies for the control of a system of k elevators with capacity one in a transport environment with I floors, an idealized version of a pallet elevator system in a large distribution center of the Herlitz P B S A G in Falkensee. Each elevator in the idealized system has an individual waiting queue of infinite capacity. On each floor, requests arrive over ...

Exact and approximate solutions of fuzzy LR linear systems: New algorithms using a least squares model and the ABS approach

We present a methodology for characterization and an approach for computing the solutions of fuzzy linear systems with LR fuzzy variables. As solutions, notions of exact and approximate solutions are considered. We transform the fuzzy linear system into a corresponding linear crisp system and a constrained least squares problem. If the corresponding crisp system is incompatible, then the fuzzy ...